Electricity>Nuclear Energy>Your friend Uranium-235

  
What have we learned so far about electricity?

•Electricity is the flow of subatomic particles called electrons

•Electrons are located in things called atoms

•Electrons will flow in a conductor when it is placed in a magnetic field

•An electric generator is essentially many conductors rotating in a magnetic field

•Electricity is free but the means to turn the generator is not

•The generator can be turned by wind, water, or (most commonly) steam

•Steam is produced by boiling water

•Heat to boil water comes most commonly by burning coal

•Another source of heat to boil water is the heat given off by a nuclear reaction

So, onward and upward, mes petits protégés.

Most of you have seemed very bored in class so far, because the information has been so elemental. Except for little Canucklehead, who often looked challenged, even during the balloon rubbing. Today, in an effort to keep you exceptional children awake, we will discuss what a nuclear reaction is, what fun things you can do with it once you have it going, and, in another post, a couple of things you probably want to watch out for. Ready?

First of all, you may recall that the nucleus of an atom consists of little things called protons and neutrons, and that electrons revolve around the nucleus. You may also remember that the number of protons in the atom tells you what "element" the material is. The names of some elements are iron, oxygen, gold, lead, helium and many others. One other example is an element called Uranium.

Uranium occurs naturally on Earth. Some elements, such as plutonium, do not. You don't have to remember plutonium though. Uranium has an atomic number of 92. Does anyone remember what that means? Ettarose? Yes, it means uranium has 92 protons in its nucleus. Good girl! Of course it also has... what?... yes, neutrons and electrons. Good, Angelika!

Uranium is a metal, considerably denser than lead, and is a silvery-gray color when refined. Ummm... like lead. Some elements have variations in their atomic structure, and these variations are called "isotopes."

Canucklehead, you have not been paying attention. Tell the class what an isotope is, please. What? A baseball player on the triple-A team owned by the Dodgers located in Albuquerque? And they serve beer there? Correct, but we are not talking about baseball right now. Pay attention, please.

You may recall that besides protons, an atom's nucleus also contains small particles called neutrons. What's that Janet? Yes, we made fun of neutrons because they had no electrical charge. Some atoms of the same element have different numbers of neutrons. Each variation in the number of neutrons is called an isotope of that element. For example, uranium-235 is one variation, or isotope, of the element uranium. Uranium-238 is another possible isotope of the same element.

An interesting thing about uranium-235 is that if you bombard its nucleus with an outside source of slow neutrons, you can make it's nucleus split apart (fission). What, Descartes? Why, yes! - just like slamming a cue ball into a group of other pool balls. Great analogy! Pow, pow, pow! ::Ralphie's old man is nervous now: "Carefull now... they go all over!"::

Yes, Lidian, very cool indeed. But that's not the REALLY cool part. No. Can you tell us what the REALLY cool part is, little A.? Little A.? Little A., don't pretend you are invisible. Everyone can see you sitting there. Anyone? Anyone? Alison?

Why, YES, little Alison! The really cool part is that when you break apart the nucleus, the pieces fly off and break apart the nucleus-us-us... nuclei... of other atoms. So cool, indeed! Thank you Alison! You have been reading your little Nuclear Reaction book, I see!

So... once you get the fission (splitting) nuclear reaction started, it just keeps going on its own! And going, and going, and going, and going... wake up Canuck.

But, another very important thing is, when the nuclei break apart, HEAT is also given off. True! Slam! Pop! Split! Burrrrrrnnn! Right, Sheila! Nine-ball in the side pocket! Go for it class! ::turns up hip hop music really loud as tykes get on their feet and duck their heads up and down to the beat:: Yes! do the "neutron slam", Debbie! Slam! Bam! Pop! SPLIT! -- Burrrrrnnnn!

Okay, sit down now, please. ::Turns off the music::

Who would like to see a picture of a nuclear reactor at work? ::Everyone raises their hands::

Look up at the projection on the wall, children. A beautiful unearthly blue. An online reactor at a nuclear power station. ::Class goes silent::

::Quietly:: "The primal power of the universe. Yes, oddly frightening..."

(To be continued in an upcoming post)

A very unusual way to boil water

In 1831, Michael Faraday discovered that if an electrical conductor (a copper wire, for example) is passed through a magnetic field, there will be an electrical current induced in that conductor. That's pretty much the essence of the story of electricity as we know it today. The refinements that we've learned since then are icing on the cake.

An electric generator is a device used to convert mechanical energy into electrical energy. That is to say, mechanical energy is used to pass that conducter through a magnetic field, and the electricity thus produced is sent through wires to your home.

"Mechanical energy" (the energy needed to spin the conductors around within that magnetic field) might be sourced from wind power or water power, but far more commonly that mechanical energy comes from steam power.

Steam is created by boiling water. The steam thus produced is blasted into a turbine which turns the electrical generator. The means used to boil the water can be oil or gas (or wood, or whatever) but by far the most common fuel used to boil water for electrical generation is coal.

Boiling water with heat made from coal is costly both in dollars and also to our environment. Janet can testify to the latter. Burning coal is also a dirty proposition and VERY expensive to make even half clean with scrubbers.

Another way to boil water is much cheaper and much MUCH cleaner (if guarded properly.) This is by using nuclear energy to produce the electricity.

A lot of people have a mental image that in order to produce electricity in a nuclear power plant, uranium fuel rods are somehow mysteriously rubbed together by scientists and electricity is given off in the process.

In reality, making the atoms in uranium excited (VERY excited!) in things called "fuel rods" simply makes the fuel rods very hot. Very hot indeed. But basically, if you cover the fuel rods with water, the water will boil and turn to steam like any other boiling water. Hence the title to this post: "A very unusual way to boil water."

Uranium is very cheap. Uranium is very efficient - it lasts for a very long time (a very long time indeed compared to coal.) Thus you have a cheap fuel that lasts for a long time which can produce steam and spin generators to make large amounts of electricity for a very long time. Very cost effective.

::Fran Drescher as The Nanny: "Sooooo....what's yer PRAHHHHH-blem???::

Well, the problem are the Homer Simpsons of the world employed at nuclear power plants who are too bored or too sleepy to do one simple thing: make sure they watch that the level of the water stays covering the uranium fuel rods. Even Dr. No knew enough to do that. (Although he, or Ian Flemming, were not all that clear on containment procedures.)

In a way this IS rocket science, but in a very real sense it is not: what idiots could not watch water level gauges and read sensors and look into tv monitors and cause water valves to be turned when needed?

What idiots? Well, the idiots at Three Mile Island for one. And the idiots at Chernobyl for another.

You see, when the water boiling on your stove boils away, the dry pan gets very hot indeed, and fires result.

When nuclear reactions are taking place and the hot fuel rods are not kept covered with water, they get very hot too. So hot they will melt anything they come in contact with. Metal. Concrete. Dirt. Ah. Dirt. They will continue melting all the way through the earth, all the way to China. The China Syndrome. That's a theory. It has never actually happened.

So, today, in the U.S., we still put up with 19th century methods of burning coal and other fossil fuels to boil water, rather than make sure idiots are properly trained and watched closely.

The last U.S. commercial nuclear power generator to go on-line was on February 7, 1996.

Of course something else happens when you don't properly keep the nuclear fuel rods and contaminated materials safely within the containment system, and that "something" certainly must not be overlooked.

[To be continued.]

[Yes, Dear A., I know all about France's fine 86% nuclear production. Just wait, please.]